The present approach relates generally to the field of breast cancer screening and, more specifically, to the use of tomosynthesis and ultrasound imaging for acquiring breast images.
In modern healthcare facilities, non-invasive imaging approaches are used for identifying, diagnosing, and treating diseases. One purpose to which such techniques are applied is the acquisition of breast images for use in identifying and diagnosing lesions or irregularities in the breast tissue.
In conventional mammography approaches, breast imaging may be implemented using radiographic techniques, such as by projecting X-rays through the breast tissue and reconstructing images based on the differential transmission of the X-rays through the tissue. Such approaches, however, may suffer from various detriments. For example, conventional radiographic imaging techniques are generally planar or two-dimensional in nature, limiting the ability of a diagnostician to visualize the results.
An alternative approach to conventional radiographic mammography involves an imaging technique known as tomosynthesis. In tomosynthesis X-ray attenuation data is obtained for a region of interest over an angular range (e.g., 30°, 45°, 90°, and so forth) and this data is used to construct volumetric or generally three-dimensional reconstruction of the breast tissue. In general, tomosynthesis imaging exhibits good in-plane resolution with, potentially, poorer depth resolution. In this manner, tomosynthesis may be employed to non-invasively detect abnormalities in the breast tissue, such as lumps, fibroids, lesions, calcifications, and so forth. Such tomosynthesis systems are generally effective for detailed characterization of benign and cancerous structures such as calcifications and masses embedded in the breast tissue.
Another imaging approach for use in imaging breast tissue is ultrasound. An ultrasound imaging system uses an ultrasound probe for transmitting ultrasound signals into an object, such as the breast of the patient being imaged, and for receiving reflected ultrasound signals there from. The reflected ultrasound signals received by the ultrasound probe are generally indicative of boundary transition between structures in the imaged region and may be used to reconstruct an image of the interior of the tissue. In general, ultrasound may exhibit good depth-resolution combined with a somewhat reduced in-plane resolution. Ultrasound imaging is useful as an alternate tool for diagnosis, such as for differentiating benign cysts and masses. In addition, ultrasound imaging may be used as a secondary screening tool in women with breasts that are dense. In dense breast tissue X-ray imaging is not as sensitive and the addition of ultrasound imaging has been shown to find more cancers.
In practice, it may be desirable to utilize multiple imaging approaches when evaluating a patient, such as by acquiring both tomosynthesis and ultrasound imaging data. To be able to relate the respective data sets, it may be desirable to acquire the image data at roughly the same time and with the patient in the same position for both data acquisitions. Hence it may be desirable to utilize a combined tomosynthesis and ultrasound imaging system that allows rapid and sequential acquisition of the respective image data sets. However, one impediment to the design and use of such systems in this manner is the interference that the various parts of one systems may have on the other system, such as the presence of an ultrasound probe in the vicinity of the X-ray beam path, and the need to minimize or coordinate the operations to be performed by the attending technologist.